AUR is really neat - you define a package by including the source, as well as any required resources, and finally you include a PKGBUILD file, which defines a list of dependencies, and provides the required build steps.
As a user of AUR, I simply pull a tarball containing all the above information, from the repository, I untar the package, and modify the PKGBUILD for my particular environment, adding or removing flags, adjusting the install location, or whatever else I want to customize. The final step is to use the
makepkg application, which run the installation scripts.